Valve motion for duplex pumps



Aug. 5, 930. G. w. voLz VALVE MOTION FOR DUPLEX PUMPS Filed March 7, 1928 5 Sheets-Sheet l INVENTOR. Gohlz'eb l W VOZZ A TTORNE YS.

Aug. 5, 1930. G. w. voLz 1,772,121

VALVE MOTION DUPLEX PUMPS Filed Max-a@ 1928 5 sheets-sheet 2 F, 16g" FZ/4 y wm-23@ Aug. 5, 1930. G. w. vo| z 1,772,121

VALV-E MOTION FOR DUPLEX PUMPS Filed March 7, 1928 5 Shees-Sheet 3 Patented Aug'. 5, 193

:PATENT orties UNITED 1stares GOTTLIEB W. VOLZ, F LONG BEACH, CALFOBNA, ASSGNOR vlO 'VOLZ ENGINEERING CORPORATION, OF LONG BEACH, CALFORNIA, A. VCORPORATION OF CALIFORNIA VALVE MOTION FOR DUPLEX' PUMPS Application iled March 7,

This invention relates to a duplex steam pump which delivers a non-pulsating flow of liquid, and pertains particularly to a valve motion for Acausing functioning of the pump 5 in such manner.

n the standard tvpes of duplex pumps, there is a pulsating delivery 'of liquid due to alternation of the working strokes of the pump members and one pump member de- .10 creasing in speed at the ends of its stroke and the other member picking up the load, the latter starting from the zero speed and increasing to full speed then decreasing in speed. As is well known, pulsation causes 4:Us racking of the pipes and fittings and pounding of the valves on vtheir seats, resulting in kleaky valves. Furthermore,'inertia oi the col-umn of liquid must be overcome. lThis results ina waste ot steam. Air chambers have been currently installed in the delivery line to overcome pulsation, but these do not remedy pulsation in the pump itself.

The present invention has tor its primary object the kprovision of a duplex pump which delivers a continuous flow of liquid without any substantial pulsation. This is accomplished by causing the pump pistons to overlap in their travel at the ends and beginning of their strokes so as to be displacing the same total amount of liquid at all times. To cause functioning in this manner, when both pistons are moving in overlapping position, the

sumv of the speeds should be equal to that of a single `piston moving at full speed. A more speciiic object of this invention is to provide a valve motion which will cause functioning of the pump in the manner above mentioned. A further object of this invention is to provide a valve motion wherein each valve is moved by the action of both pistons. A still further object of this invention is to provide a valve lmotion Aof the character described wherein the opposite piston produces most of the Vvalve travel so as to maintain step.

These objects together with other objects and corresponding accomplishments are obtainedbymeans of the embodiment of my invention illustrated in the accompanying drawing in which 60 Fig. lisa perspective view of a complete 1928. Serial No. 259,673.

pump with portions of the steam chestand steam cylinders broken away to better illustrate the invention; Fig 2. vis aside .elevation of the pump showing the steam end insection; Figs. 3 to 8 inclusive arediagrammatic views of the steam valves and associated steam cylinders in various travel positions, and Figs. 9 to 1aare elevations of the steam ends partly in section showing positions of steam pistons, steam valves, and the valve motion at diEerent travel positions. In Figs. 9-to 14;, the contiguous ymembers Vof the steam end are shown opposed for better illustration .of the action. Thus, Figs. 9 and l0 show .a pair in corresponding positions in their -travel. Likewise Figs. l1 and l2 show the same pair in another position, and Figs. 13 and 14 show them in stillanother position.

Referring more particularly -to'Figs 4l and 2,the pump end A may be of any well known double acting typecomprising two pumps side by side with suitable plungers and valves. 'The speciiicconstruction is not pertinent to the lpresent invention, ,the steamend B comprising two steam cylinders with pistons and valves. The valve motion is indicated generally by C. 'Referring-.more .specifically to thesteam end, ,the parts are similar Yfor each member andare marked with the same reference numerals,'but with alpha.- betical indices appended, a for one' mem* ber and b ,for the other. The steam cylindersvare shown in a single block.

The steam cylinder .l5a has `reciprocabl-y mounted therein a .piston 16a with `a l,piston rod 1"?ZL secured thereto.` This-redis connected to the corresponding'pump plu-nger. There is -a common steam chest .18 having `a valve seat d119. .In the seat are steam inlet ports 20a and 2l?. Between the Vsteam Iports is .-an .eX- haustport 22a. Riding on the valve seat isa slidevalve 23a of the D type having an eX- lhaust cavityQia. yUpstanding from the valve arespaced ltappet abutments '25a and 26a. A valve rod .27a .has .a .tappet28a Adisposed be- 95 tween the itappet abutments so `as to provide a lostJ motion connection. The valverod lis slidably supported at .its .end in a socket .in `bracket 30.

A box 212L having .aslot .thereinfissecured In@ to valve rod 2751. Pivotally mounted in the slot is a floating lever 3f. The lower end ot the lever is connected by a link 831L to a rocker arm 34a pivotally mounted in the bracket at the upper end, the lower end being received in a slide box 3 52L attached to a piston rod 17a. The rocker are 34a is iiXed to a shaft 36a to which an upwardly extending crank arm 371 is connected forming a bell crank lever. Valve rod 271 has a boX 311J in which is pivoted a floating lever 3211. The lower end of lever 321J is connected by a link 331) to rocker arm 341. lt will be noted that while rocker arms 3431 and 341 are corresponding elements,

.one is longer than the other because ot the necessities of compact assembly otparts.

ltocker arm 34:1) is attached to a shaft 361* journalledV in bracket 30. Attached to the other end is a depending crank arm 37a torming a bell crank lever. Crank arm 37a is connected by a link 38a to floating lever 32a inter- -lll mediate its ends. Crank arm 371 will oscillate at its upper end in the opposite direction to the rocker arm 34a. Crank arm 371 is connected by a link 88h to the iioating lever 321 intermediate its ends. It will be noted that each valverod is connected by linkage to bot-h piston rods so that its movement is effected by the two pistons.

Referring to Figs. l and 2, piston 161 is shown moving outwardly and has approached near the end of itsstroke. Valve 231 is near its outer position, half uncovering steam port 201. Tappet 281 is engaged with the inner tappet abutment on valve 231) and moving inwardly. Movement of piston 1611 outwardly causes rocker arm 34:11 to be swung outwardly. l

Motion is transmitted from the rocker arm to floating lever 321 moving the lower end outwardly. Piston 16a has started its movement 'y outwardly. Valvev 23a is near its outer position, haltuncovering port 20a. Halt ot' the steam at full port opening of a single port is entering cylinders laand 1511. rl`his results in half speed oteach piston and its pump plunger and the total or cumulative displacement per unit of time is equal to the displacement at full port opening of one piston, which is hereinafter termed normal displacement. Movement ot piston i6DL outwardly causes rocker arm 34a toy be swung outwardly7 and with it crank arm 371 in an inward direction. rlhis causes a movement of the intermediate part of floating lever 321) inwardly. Rocker arm 341 is being swung outwardly by reason of the outward movement of piston 161 -and acts upon the lower end of the lever 321) to move it outwardly. The differential movement causes the top of the floating lever and valve rod 271 to be moved inwardly toward closing` position of steam port 2011. Rocker armi-la being swung outwardly causes the lower end of floating lever 32a to be swung outwardly. Rocker arm 341 being swung outwardly causes crank arm 37a to bejswung outwardly. The composite motion causes valve 23a to be moved outwardly. Fig. S'shows diagrammatically the positions of the pistons and valves and the appended arrows their directions of motion. Valve 23 is continued in its movement toward full opening of port 20a. l/Vhile valve 231 is continued in its move-V pump is delivering the normal Aamount ot" liquid. rlhe valve rod rtappet 281 is at the outer end of its travel engaging the outer tappet abutment. ylhe valve rod 271 can now be moved inwardly a limited distance without causing movement ot the valve 231. ln the position shown in Fig; 9, the piston rod 171 is at rest so that the lower end o1 rocker arm 34th in boX 851l is stationary and link 331 is likewise stationary. Movement is then only obtained through link 381 which is aotuated from piston 16a. l0, piston 16a and its valve 23a, it will be noted that the piston has been moved about one-quarter ot its outer stroke. Steam port 20a is fully uncovered. On the outer travelV to crank arm 371J and lever 321 inwardly, with Reterring to F ig.

Vloo

the result that valve rod 271 will be started on A its inner travel. However, valve rod 271J must be moved until tappet 281) engages the inner tappet abutment before the valve 231 is started on its inward travel. rhere is theretore an interval during which valve 231r remains in position closing its steam ports and valve 23a with its ports 2On :tull open. Arm 341 being stationary, crank arm 37 is likewise stationary causing link- 38a to hold lever 822l stationary at its center. Movement of lever 3 a is effected through rocker arm 34a and link 33a to cause valve rod 27a to be moved inwardly. Tappet 2821 travels from the outer tappet abutment to theA inner before caus- 'the position ot the valves and pistons .correspending to Fig. 9 and 10 is shown diagram# matically.

A next succeeding position of the parts is illustrated diagrammatically in Fig. 5. It will be noted that due to the lost motion between the tappets and valves, the piston 16a has moved inward to a position about threequarters et its stroke and piston 1Gb remains stationary at the outer end of its stroke, Without either valve 23 or 23h being moved.

rFhe next succeeding position is shown in I Figs. 11 and 12 and diagrammatically in Fig. 6. The tappet 28" has engaged the inner tappet abutment on valve 23h and moved the latter so as to half uncover port 2lb, admitting steam behind piston 16h and starting it on its inward travel. This causes swinging ol rocker arm 34h inwardly and acts to swing the lower end of floating lever 32h. Rocker arm 8 a is bein'g swung outwardly causing crank arm 37b to be swung inwardly moving valve 23h toward opening position of port 211. Referring to its companion, rocker arm 34 is being moved outwardly7 tending to swing lever 32a and valve rod 27a inwardly. However, movement of rocker arm 348 transmits motion through crank arm 37, hastening the movement of the valve rod 2@ and valve 23 inwardly toward a position covering steam port 20a. The position is illustrated diagrammaticaly in Fig. 6. Both ports f2.0L and 21b are half uncovered admitting steam to their respective cylinders in haltl the fully uncovered amount and causing the pistons to travel at half speed. Both pumps are delivering one-hall the amount ol liquid that they would normally. Their total is theretore the full normal amount. The next succeeding position of the pistons is shown in Fig. 7 Piston 16a has completed its outer stroke and piston 16b about one quarter of its inward stroke. The valve 23a has been moved to steam port closing position and valve 23h to full steam port open position. The ports are in opposite position to that shown in Figs. 9 and 10. Valve 23a is stationary in full closed position. Valve 231 is at the endv of its inner travel. Valve rods 27a and 27h are now started back and due to their lost motion, the valves remain stationary for an interval. Piston 16a remains stationary and 16b continues the remainder of its three-quarter stroke. However, valve 23a is continued on its inward travel, while valve 231 is stationary and thereafter started on its inward travel to the position shown in Figs. 18 and 14.

The next position illustrated in Fig. 8 shows the valves traveling in opposite direction, the ports 212L and 21b each halt open and the pistons both traveling inwardly. The piston 17b has about completed its stroke and piston 17a is just starting. l The pistons and valves are at the opposite ends oi their travel to that shown in Fig. 3, and the movements will be accomplished in the reverse dir e'eton in correspondence Ywith those already described.' y A It will be noted thatthe sum et the total 'port areas open at any' one time is always substantially equal to one port fully opened;

yfurthermore', that when one piston is at the end oi its stroke, the other is traveling at full speed; and still further, .that when one piston is decreasing in speed, the other is increasing so that the total displacement speed is always the same.`- The lost Vmotion connection between the valve rods and tappets permits one valve to remain fully open tor an interval and during that interval the other valve to remain fully closed.

lt will Abe further noted that at no timeare both pistons stationary, one always'travelling at 'full port opening while the other is stationary and one piston starting its return stroke. before the other reachesth'e end. ot its stroke. There is thus an overlapping of the working travel of the pistons at both ends of their strokes thereby'maintaining a continuous flow ot water without any substantial pulsation.

What I claim is 1. ln a duplex pump having reciprocating plunger mechanism, a duplex reciprocating motor for reciprocating said plunger mechanism including valves for each motor mem ber; control mechanism for said motor actuated from said motor mechanism including a lever ior operating each valve,'each lever being connected at Vone end to a valve to operate the latter, being connected at the other end to one of the members of said plunger mechanism to produce a component of oscillatory movement and being connected intermediate said ends to the other member of said plunger mechanism to produce a como ponent of oscillatory movement, said plunger mechanism thereby producing composite motions whereby to alternately cause normal displacement of the plungers at intermediate portions of their strokes and overlapping oi:T their strokes at the ends to eiect cumulative normal displacement of said plungers.

2. In a duplex pump having reciprocating plunger mechanism, a duplex reciprocating fluid actuated motor for reciprocating said plunger mechanism, slide valves for said motor, valve stems; and a valve motion actuated by said plunger mechanism and controlling said valves including a lever for operating each valve, each lever being con-"if nected at one end to a valve stem to operate the latter, being connected at t-he otherend to one of the members of said plunger mechanism to produce a component of oscillatory movement and being connected intermediate said ends to the other member of said plunger mechanism to produce acomponent of oscillatory movement, said plunger mechanism thereby producing composite motions whereby alternately to fully admit actuating fluid to oneinember of the motor at an intermediate portion of itsstroke and to ma1ntain the other member of the Amotor stationary, and to admit actuating Huid to both members at the ends of their strokes in ay cumulative amount substantially i equal to full admission to one member.

.3. In a duplex pump having reciprocating plungers, a duplex reciprocating iiuid actuated motor having piston rods, one connected to each plunger, slide valves for said motor controlling inlet ports thereto; a valve motion including linkage, one for each valve,

each linkage including a lever for operating each valve, eachy lever being connected at one end to a valve to operate the latter7 being connected at the other end to one of said piston rods to produce a component of oscil latory movement and being connected intermediate said ends to the other of said rods to producea component of oscillatory movement, said piston rods thereby producing a composite motionwhereby to operate said valves so'as to fully open an inlet port to one of the members of said motor at the intermediate portion of its stroke and maintain the inlet port of the other member closed, and to open inlet ports to both members at the ends of their strokes in a cumulative amount substantially equal to iull port opening.

In Witness that I claim the foregoing I have hereunto subscribed my name this 24th day of February, 1928.

Y GOTTLIEB W. VGLZ. 

